In the most commonly used glassware forming machine known as the Hartford IS Machine, a plurality of independent or individual sections are operated in timed relationship to each other and each section receives gobs of molten glass from a feeder generally centrally position with respect to the number of sections in the machines. The gobs are received at the blank or parison forming station of each machine section and with the blanks upwardly open, parisons are formed in the inverted orientation in the blank molds and are subsequently swung over to the blow side for final forming in blow molds. The neck ring mold cooperates at the blank mold for forming the neck of the parison and serves to provide the support to the parison as it is inverted by the operation of an invert arm which carries the molds. The split parison molds, when they are a plurality, are, for the most part, in a conventional IS Machine, hinged from a hinge-pin that is in alignment with the axis of the parisons, or parison molds, and the arms then are moved about the hinge to open and close the split parison molds. Reference may be had to U.S. Pat. No. 3,472,639 which shows such a parison mold holding mechanism. This method of forming articles of glassware has been practiced since the 1920's.
These pivotally mounted mold arms have disadvantages, some of which are related to the differences in degree of mold opening provided between a double or triple gob machine operation. It should be understood that it is necessary that the mold holders and the mold halves carried thereby be capable, on the parison side, of opening in an amount sufficient to permit the invert arm to clear the open molds. Obviously, the mold half adjacent the hinge-pin necessarily opens less than do those more remote from the hinge-pin. Generally speaking simply increasing the angular travel of the pivotally mounted mold support arms cannot be tolerated where the machine is already overcrowded due to space limitations within each of the side by side sections. As might be expected the hinge-pin as it wears will result in the mold themselves not cycling on the same centers each time and in fact it is a constant maintenance problem in keeping the mold mechanisms in alignment over extended periods of operations of machines.
Another disadvantage relates to the requirements for cooling the molds and the use of fixed wind of horns as has been the practice with the horns positioned to feed air against the backs of the molds. It can be seen that this system of cooling is perhaps not as economical as one in which the air will be brought into the mold holders and then distributed evenly to the backs of the molds in a controllable manner.